A semiconductor die typically generates a significant amount of heat and is required to be cooled for reliable operation. Existing cooling techniques are limited to the removal of heat through a back side of the semiconductor die. For example, a heat sink or a fan may be mounted to the back side of the die in order to remove heat. However, most of the heat is generated at a circuit side of the semiconductor die which is remote from the back side and because of thermal resistance between the circuit side and the back side, the effectiveness of cooling by heat removal through the back side of the semiconductor die is reduced.
FIG. 1 of the drawings shows a semiconductor package 100 which includes a cooling mechanism that is illustrative of the above-described cooling techniques. Referring to FIG. 1, the semiconductor package 100 includes a semiconductor die 102 which is bonded to a substrate 104 by a plurality of conductive bumps 108. The semiconductor die 102 includes a back side 102.1 and a circuit side 102.2. Mounted to the back side 102.1 is a heat sink 106 which includes a plurality of thermal fins 106.1. Typically, the heat sink 106 is of a conductive material which operates to draw heat by conduction from the semiconductor die 102 and to radiate the heat through the fins 106.1. It will be appreciated that the larger the surface area of the fins 106.1, and the larger the area of the heat sink 106 that is in contact with the semiconductor die 102, the more effective the cooling. Accordingly, as semiconductor dies reduce in size, the effectiveness of cooling by mounting heat sinks to a back side of a semiconductor die is reduced, since the available semiconductor die back side area is reduced.